Compressor and vacuum pump



April 19, 1932. H. COOPER 1,854,692

COMPRESSOR AND VACUUM PUMP Filed April 30, 1927 2 Sheets-Sheet l a *4f I 1 l l .4 i

April 19, 1932. H, CQOPER 1,854,692

COMPRESSOR AND VACUUM PUMP Filed April 30, 192'? {Sheets-Sheet 2 /m/emor 77 70 44 3 5 Z7 fenerz Cooper by Waff; QM@

Patented Apr. 19, 1932 UNITED STATES PATENT OFFICE HERBERT COOPER, OF BROOKLYN, NEW YORK, ASSIGNOR TO COOPER COMPRESSOR COM- PANY, OF BROOKLYN, NEW YORK, A CORPORATION DELAWARE COMPRESSOR AND VAUU UM PUMP Appncilibn mea April so,

This invention relates to compressors and vacuum pumps for air and other gases, and more particularly to machin-es of the type having a rotary member which is eccentrically mounted within a cylinder and provided with blades movably mounted in slots therein and which engage the inner face of the cylinder, thereby forming pockets within whic the air is gradually compressed as the rot-or turns, due to the progressively decreasing volume of the space between it and the wall of the cylinder.

In prior machines of this type the blades are radially arranged and are forced outwardly against the face of the cylinder by mechanical elements or centrifugal force. Considerable diiiicultyis encountered in maintaining sutliciently tight contact between the ends of the blades and the heads of the cylinder to prevent leakage from the pockets of higher pressure to those of lower pressure. The use of mechanical elements for forcing the blades outwardly has many disadvantages.

It is an object of this invention to improve compressors and pumps of the type described above by increasing their efficiency and simplifying their construction. This is attained by offsetting the blades from the radial position of prior machines and utilizing them as pistons to compress air at the bottoms of the slots within which they are placed, these slots being placed in communication with the air intake port when the blades are in their outermost positions and in communication with the outlet port when the blades have "been forced into their innermost positions during the rotation of the rotor. By virtue of the compression thus obtained in the slots, the machine acts as a combined rotary and reciprocating compressor with correspondingly increased compression and without the use of mechanical elements as the compressed air in the slots forces the blades outwardly against the cylinder. Therefore with identical dimensions and speed the compressor delivers more air than does one of the type described above and is independent of s rings, push-rods or centrifugal force for orcing the blades against the cylinder.

1927. Serial No. 187,893.

The non-radial arrangement of the blades permlts deeper slots and wider blades thus increasing their wearing surfaces and reducmfg the tendency for leakage around them.

' A urther feature of the invention is the provision of inclined faces of the blades and bottoms of the slots, whereby the longitudinal component of the air pressure in the spaces at the bottoms of the blades will force their ends against the heads of the cylinder to prevent leakage. This force is progressively greater during each revolution of the rotor, being a minimum at the air intake and a maximum at the air outlet. This saves power, as there is no necessity of forcing the blades against the cylinder and its heads, by any means, beyond the amount necessary to prevent leakage.

Another feature of the invention is the provislon of an inner head for one end of the cylinder, which may be accurately adjusted to reduce the clearance at each end of the rotor to the minimum required to prevent leakage. This adjustment may be made mechanically or the movable head may be forced against the rotor by the pressure within the compressor with suitable limiting screws to prevent the head from binding on the rotor.

An oil separator is associated with the compressor in which the oil collects after being separated from the air and is then forced under pressure to the adjustable head and from it to the bearings and interior of the cylinder to lubricate the rotor and blades, the surplus oil being carried into the separator by the stream of compressed air.

The particular nature of the invention as well as other objects and advantages thereof will appear most clearly from a description of a preferred embodiment as shown in the accompanying drawings in which Fig. 1 is an elevational view taken in section through the centre of the entire machine.

Fig. 2 shows the rotor of the machine with two of its blades removed.

Fig. 3 is an elevational view of the compressor part of the machine in section along the line 3-3 of Fig. 1, and Figs. 4 and 5 are end view and sectional view in longitudinal cross Ico section respectively ment of rotor.

In the drawings 1 indicates generally the compressor part and 2 the oil se arator art. The former 1s composed of a cy lnder 3 av ing inner and outer walls 4 and 5 respectively, between which is a chamber 6 for a cooling liquid, such as water. The cylinder is ro= vided at one end with a head 7 attached) by screws 8 and havin a chamber 9 communieating with the camber in the cylinder through a passage 10. Cooling liquid is supplied to the chambers through an inlet port 11 in the head.

The head is also provided with a bushing 12 for a bearing 13 for the shaft 14 of the rotor 15 of the compressor which will be hereinaterdescribed.' A gland 16 is screwed on to the bushing with packing 17 to make a tight lit around the shaft and prevent leakage of air from the compressor.

At the other end of the cylinder is an outer head 18 attached by screws 19 and having a chamber 20 communicating with the chaml ber 6 in the cylinder through a port 21. The

head 18 is provided with an outlet port 22 for the cooling liquid.

Adjustably attached to the head 18 is an inner head 23 forming the actual closure for the correspondin en of the cylinder within which it 1s fitte For the purpose of adjustin the inner head there is attached to it a num er of screws 24 which pass through bushings 25 screwed into the outer head 18 and contacting at their inner end with the outer face of the inner head. The heads of the screws 24 are concealed by ca s 26 screwed into the outer ends of the bushmgs 25. By adjusting the screws and the bushings the inner head 23 may be accurately positioned with respect to the rotor to reduce the clearance between it and the head to a minimum and prevent leakage from this end of the cylinder.

The inner head 23 is provided with a bushing 27 for a bearing 28 for the other end of the rotor shaft 14. There is a port 29 for the flow of oil that returns from the separator'to the chamber 30 between the outer and inner heads 18 and 23 respectively into the interior of the cylinder to lubricate the rotor.

The inner face of the inner head 23 is provided with a recess 31 extending upwardly from the bottom portion of the cylinder and another recess 32 extending downwardly from the upper portion of the cylinder where it communicates with a passageway 33 leading from the interior of the cylinder to the oil separator to be hereinafter described.

' The rotor of the machine consists of a cylindrical member 34 keyed on the shaft 14 and provided with a plurality of inwardly non-radial slots 35 within which are slidably mounted blades 36 provided with bevelled of a modiiied arrange;

outer ed es adapted to enga e the inner face of the cy inder, as shown in ig. 1. The bottoms of the slots are inclined, as indicated at 37 in Fig. 3, adjacent slots being inclined in opposite directions or in other words, alternate slots are inclined in the same direction.

The rotor is eccentrically mounted in the cylinder, as shown most clearly in Fig. 1, thus providing a chamber of progressively decreasing volume from the air inlet port in the walls of the cylinder to the discharge passageway 33. The inlet port is in the form of circular aperture 38 communicating with a relatively narrow assage 39 leading downwardly in to the cylinder, as shown in Fig. 1.

Screwed into the discharge port 33 is a tube 40 closed at its upper end by a plug 41 and provided in its side with downwardly ,extending apertures 42. Surrounding the tube 40 is a casing 43 consisting of an inner wall 44 having a dome-shaped top and a cylindrical outer lwall 45 provided with a port 46 for an oilgauge of any suitable type. A second dome-shaped vmember 47 is mounted upon the top of the inner wall by lugs 48. A cover 49 is screwed upon the top of the outer wall 45 and serves to center the member 47 and prevent it from being displaced, by means of lugs 50 with which it is provided and which engages the side of a recess in the cover at the bottom of a discharge port 51.

A passageway 52 is provided at the bottom of the inner wall 44 to place the chamber between the inner and outer walls in communication with the interior of the casing 43. A second passageway 53 leads from the top of the casing of the compressor portion immediately below the passageway 52 to the top of the chamber between the outer and inner heads 18 and 23 respectively. A screen of Wire mesh 54 is placed in the chamber between the inner and outer walls of the separator to aid in separating the oil from the air.

In the operation of the machine the rotor revolves in the direction indicated by the arrow in Fig. 1 and in doin so draws air into the pockets between the lades 36 through the intake port 38 and passage 39, some of the entering air flowing through the recess 31 into the space at the bottom of each blade as it comes 1nto communication with the recess. The air in the pockets is gradually compressed as they decrease in volume due to the eccentricity of the rotor in the cylinder until it finally escapes through the outlet 1 port 33 into the separator.

As the blades are forced into their slots by the rotation of the rotor, the air in the spaces at the bottoms of the slots is compressed gradually and finally escapes through 1 the recess 32 as each space comes into communication with it and thence flows into the discharge port with the other compressed air.

The plug 41 forces the air to iow through the aperture 42 and into the inner chamber of 1 v the rotor to brin the separator from which it escapes at the top an then passes under and over the member 47, finally being discharged through port 51 to a suitable reservoir. During its passage throu h the separator the air gives up its oil wh1ch flows into the bottom of the separator and then through assages 52 and 53 into the compressor where 1t fills the chamber 30 and iows into the cylinder through aperture 29 to lubricate the rotor and its blades and bearings.

The inner head 23 may be accurately adjusted against the end of the rotor by the micrometer arrangement consisting of screws 24 and bushings 25. The eiect of the air pressure beneath the inclined inner ed es of the blades will force them longitudina ly of their ends into close fit with the heads o the cylinder. Any number of blades may be used according to the r uirements of the machine.

ince the oil in the space 30 between the outer and inner heads is under the pressure of the compressed air in the separator, it may be used for forcing the inner head against the rotor. In such a case the screws 24 would be arranged to act as limiting screws to prevent the inner head from being pressed too closely against the rotor,` there eing a slight clearance between the inner ends of the bushings 25 and the inner head to ermit movement of the latter.

n Figs. 4 and 5 there is shown a modified form of rotor in which each slot in the rotor is made-by adjacent cuts of opposite angularity at their bottoms as indicated at 55 and 56 in Fig. 5. In each slot are placed two contacting blades 57 and 58 having bottoms of opposite angularity to correspond with the bottoms of the slots. With this arrangement longitudinal pressure against the heads on both ends of each pair of blades is ob- While certain preferred embodiments of the invention have been disclosed, it will be understood that variousl other changes may be made in the details of the machine Without departing from the principle of the `1n- .vention as defined in the appended claims.

I claim 1. A compressor and vacuum pump comprising a cylinder provided with intake and outlet ports, a rotor eccentrically mounted in the cylinder and provided with .a plurality of slots the bottoms of which are inclined to the axis of the rotor and blades in the slots having correspondingly inclined inner edges, the outer edges of the blades engaging the inner face of the cylinder to form pockets the volume of which is gradually decreased as the blades move from the inlet to the outlet ports during rotation of the rotor.

2. A compressor and vacuum pump comprising a cylinder provided with intake and outlet ports, a rotor eccentrically mounted in the cylinder and provided with a plurality of non-radially arranged slots the bottoms of which' are inclined to the axis of the rotor and blades* in the slots Vhaving correspondlngly inclined inner edges the outer edges engaging the inner face of t e c linder to form pockets the volume of which 1s gradually decreased as the blades move from the inlet to the outlet ports during rotation of the rotor.

3 A compressor and vacuum pum comprising a cylinder provided with inta e and outlet ports, a rotor eccentricall mounted in the cy inder and provided wit a -plurality of slots the bottoms of which are alternately oppositely inclined to the axis of the rotor and blades in the slots having correspondingly inclined inner edges, the outer edges of the blades engagin n the inner ace of the cylinder to form poc ets the volume of which is gradually decreased as the blades move from the inlet to the outlet ports during rotation of the rotor.

4. A compressor and vacuum pump comprising a cylinder provided with intake and outlet ports, a rotor eccentrically mounted in the cylinder and provided with a lurality of slots, the bottoms of ,each of whic are oppositely inclined to the axis of the rotor and a pair of blades in each slot each having an inner edge inclined correspondingly to the bottomv of the portion of the slot within which it is placed, the outer edges oftheblades engaging the inner face of the cylinder to form pockets the volume of which is gradual-l ly decreased as the blades move from the inlet to the outlet ports during rotation of the rotor.

5. A compressor and vacuum pump comprising a cylinder provided with intake and outlet ports, a rotor eccentrically mounted in the cylinder and provided with a plurality of slots the bottoms of which are inclined tothe axis of the rotor and blades in the slots having correspondingly inclined inner edges and outer edges engaging the inner face of the cylinder, said cylinder being provided with a passage to provide communication between the bottoms of the slots and the space between the rotor and the cylinder near the inlet port when the slots occupy a predetermined position during rotation of the rotor and a second passage to provide communication between the bottoms of the slots and the space between the rotor and the cylinder near the outlet port when the slots occupy a second predetermined position during rotation of the rotor.

6. A compressor and vacuum pump comprising a cylinder provided with intake and outlet ports, a rotor in the cylinder having a shaft and provided with a plurality of slots, blades in the slots with their outer edges in engagement with the inner face of the cylinder, a head attached to one end of the cylinder and having a bearing for the shaft of the rotor a head attached to the other end of the cylinder, an inner head fitted within the same end of the clinder and having a bearing for the shaft o the rotor and means connectingl the inner head to the corresponding outer ead and o erable to move the latter in opposite directions with respect to the former whereby the clearance between the inner head and the roto!` may be accurately adjusted.

7. A compressor and vacuum pump comprising a cylinder provided with inlet and outletports, a rotor eccentrically mounted in the cylinder and provided with a plurality of slots, blades in the slots with their outer edges engaging the inner face of the cylinder, outer heads for the cylinder, an inner head for the cylinder adjustably connected to one of the outer heads and rovided with a port leadingto the interior oi) the cylinder, and an oil separator in communication with the outlet port, said cylinder being provided with a passage for the How of oil from the se arator to the space between the inner an outer heads whereby it may ilow therefrom through the port in the inner head to lubricate the rotor and blades. v

8. A compressor and vacuum pump coinprising a cylinder provided with inlet and outlet ports, a rotor eccentrically mounted in the cylinder and provided with slots, blades in the slots with their outer edges in en agement with the inner face of thecylin er, a casing in communication with the cylinder through the outlet port, outer heads for the cylinder, an inner head movably -mounted in one end of the cylinder and spaced from the corresponding outer head, said cylinder being provided ,with a passage communicating with the interior of the casing and the space between the inner and outer heads whereby the iiuid ressure in the casing forces the inner head against the rotor and means between the inner and outer heads for limiting such movement of the inner head to prevent it from binding the rotor..-

9. A compressor and vacuum pump com- A prising a cylinder provided with inlet and outlet ports, a rotor eccentrically mounted in the cylinder'and provided with slots, blades in the slots with their outer edges in engagement with the inner face of the cylinder, a casing in communication with the cylinder through the outlet port, outer heads for the cylinder, an inner head movably mounted in one end of the cylinder and spaced from the corresponding outer head, said cylinder being provided with a passage communicating with the interior of the casing and the space between the inner and outer heads whereby the fluid pressure in the casing forces the inner head against the rotor and adjustable means for preventing the fluid pressure from forcing the inner head against the end of the rotor to such a point that it will bind the rotor.

10. A com ressor. and vacuum pums omprising a cy 'nder' provided with hea and intake and outlet ports, a rotor eccentricall mounted in the cylinder and provided wit a slot and a, blade in the slot'having its inner edge inclined to the axis of the rotor whereby fluid pressure in the slot forces the wider end of the blade into contact with the corres ondin head of the cylinder, the outer-ed e o the b ade engaging the inner face of t e cylinder to form a ocket4 the volume of which is graduall creased as the blade moves from the et to theoutlet ports during rotation ofthe rotor.

11. A compressor and vacuum pum comprising a cylinder provided with inta e and outlet ports, a rotor eccentrically mounted in the cylinder and provided with a plurality of slots Aand blades in the slots having their inner edges alternately oppositely inclined to the axis of the rotor, the outer edges of theblades engaging the inner face of the cylinder to form pockets the volume of which is gradually decreased as the blades move from the inlet to the outlet ports during rotation of the rotor.

12. A compressor and vacuum pum comprising a cylinder provided with inta e and outlet ports, a rotor eccentricallyy mounted in the cylinder and provided with a slot and a pair of blades in the slot 'having their inner edges oppositely inclined with respect to the axis of the rotor, the outer ed es of the blades en aging the inner face o the cylinder to orm pockets the volume of which is graduallyidecreased as the blades move fromthe inlet to the outlet ports during rotation of the rotor.

13. A compressor and vacuum pum comprising a cylinder provided with hea and intake and outlet ports, a rotor eccentrically mounted in the cylinder and provided with a plurality of slots and blades in the slots having their inner edges inclined with respect to the axis of the rotorwhereby fluid pressure in the slots forces the wider ends of the blades into contact with the correspondin head of the cylinder and said blades having their outer edges engaging the inner face of the cylinder, said cylinder being provided with a passage to provide communication between the slots and the space between the rotor and the cylinder open tothe inlet port when the slots occupy a predetermined position during rotation of the rotor and a second passage to provide communication between the slots and the space between the rotor and the cylinder open to the outlet port when the slots occupy a second predetermined position during rotation of the rotor.

In testimony whereof I aix my signature.

HERBERT COOPER. 

